1. Field of the Invention
The present invention relates to an endoscope where an end of a curved section protective sheath is affixed to an endoscope front end or a connection pipe for connecting a curved section with a flexible section with a filamentous member, and a method for manufacturing the endoscope.
2. Description of the Related Art
In an endoscope, its curved section is provided by allowing a braided pipe to cover a curved pipe having a plurality of curved pieces connected with each other and subsequently allowing a tubular curved section protective sheath made of rubber to cover the braided pipe. In the curved section protective sheath, its front end is arranged to cover the outer periphery of the endoscope front end, while its rear end is arranged to cover a connection pipe for connecting the curved section with a flexible pipe. The front end and the rear end of the curved section protective sheath are respectively affixed to the outer periphery of the front end of the endoscope and the outer periphery of the connection pipe by a wound filament to waterproof the interior of the endoscope.
To prevent the filament from coming off, conventionally, there is known a technique of applying an adhesive agent onto a wound filament to cover it in the adhesive agent (see Patent Document No. 1). Instead of using the adhesive agent, alternatively, there is a case of either using another filament whose outer periphery is covered with thermoplastic resin (see Patent Document No. 2) or arranging an annular exterior body made of thermoplastic resin on the wound filament (see Patent Document No. 3). In common with these cases, after arranging a heat-shrinkable tube to cover the wound filament or the exterior body, heat is applied to the heat-shrinkable tube, so that the filament is covered in molten thermoplastic resin. In Patent Document Nos. 2 and 3, after being heated, the heat-shrinkable tube is detached from an end of the sheath.
Patent Document No. 1: Japanese Unexamined Patent Publication (Heisei) No. 6-319677
Patent Document No. 2: Japanese Unexamined Patent Publication No. 2008-55052
Patent Document No. 3: Japanese Patent Publication No. 4236305